Device for amalgamation of gold and silver



31, 1967 TADAICHI HASHIMOTO 3,349,908

DEVICE FOR AMALGAMATION OF GOLD AND SILVER Filed March l, 1965 INVENTOR.

Tadaichi Hashimofo ATTORNEYS United States Patent 3,349,908 DEVICE FOR AMALGAMATION OF GOLD AND SILVER Tadaichi Hashimoto, Denver, Colo., assignor to Charles F. Shepherd, Denver, Colo. Filed Mar. 1, 1965, Ser. No. 436,214 Claims. (Cl. 209-185) ABSTRACT OF THE DISCLOSURE Amalgamation apparatus having a closed container with separate input means for a continuous charge of metallic ore and water under pressure into the container, with mercury delivered to the bottom and water directed in a tangential flow toward an inner upright wall portion above the mercury bed to maintain centrifugal circulation therein. Tubular siphon members with lower portion submerged in mercury moving amalgam through the submerged intake. Similar apparatus may be in series with amalgam discharge of one providing feed for next in series. Final discharge feeds to an extractor for separation of gangue from amalgam.

My invention relates generally to amalgamation apparatus and more particularly to improved amalgamation apparatus which is automatic, self-adjusting, and may be used continuously or intermittently for extracting valuable metals from a feed ore.

Amalgamation of valuable metals such as metallic gold or silver is carried out by contacting particles of these metals with mercury surfaces. Batch-type amalgamation apparatus is usually not adapted to be operated continuously and the mercury bed is stationary, thereby limiting the capacity of metal to mercury surface contact. For transport of the ore to and through the mercury substantial quantities of water are required. To carry out a process of continuous amalgamation, close regulation of the various inlet and discharge parameters is required.

Accordingly, it is the object of my invention to provide improved amalgamation apparatus in which the mercury surfaces are more efficiently contacted with the metal particles.

It is another object of my invention to provide improved amalgamation apparatus which may be used when only limited quantities of water are available.

A further object of my invention is to provide improved amalgamation apparatus which may be operated continuously with simple control for the inlet and discharge parameters.

Still another object of my invention is to provide improved amalgamation apparatus which is automatic and self-adjusting and may be operated intermittently or continuously as required.

Another object of my invention is to provide improved amalgamation apparatus which may be easily connected in series with similar apparatus for additional amalgamation.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For better understanding of my invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a diagrammatic view of amalgamation apparatus embodying my invention shown in flow sheet relation; and

FIG. 2 is a sectional view taken along line 2--2 of Y FIG. 1.

Referring now to the drawings, amalgamation apparatus illustrated in FIG. 1 comprises a flask-like container 1 having from bottom to top a flat bottom portion, a lower conical portion tapering outwardly, an intermediate conical portion tapering inwardly, and an upper cylindrical neck portion. A plug or cap 2 fits into the top of the neck portion to close the container and maintain it as a pressure chamber.

A tubular inlet member 3 extends through the side Wall of the container and terminates in close proximity to and in spaced relation with the bottom of the container. A preselected quantity of mercury is supplied through the tubular member 3 to provide a bed of mercury 4 in the bottom of the container and such supply may 'be continuous or intermittent as desired.

A conduit 6 is provided for introducing a continuous feed of comminuted metallic ore into the interior of container 1. Conduit 6 extends through the closure cap 2 in a sealed relationship and has an exterior portion extending above the container 1 and an interior vertical portion extending within the neck portion through substantially its length for discharge of feed into the lower portion of the container. An overflow control tube 7 extends upwardly from an exterior portion of feed conduit 6 to discharge any excess water accumulated in the container during a particular phase of operation in a manner described more fully hereinafter.

The lower conical portion of container 1 has an inlet conduit or distributor 9 having one outlet 9a or a plurality of outlets in selected spacing on the side of the container and extending through its inner wall arranged to direct incoming water under pressure in tangential flow toward the inner wall of container 1. A suitable pump 10 is provided in inlet conduit 9 to introduce the water under the required pressure to circulate the water in a centrifugal flow around the interior wall of the container and to distribute the incoming ore particles over the mercury bed surface.

Disposed centrally in the container there is provided a generally tubular siphon tube 12 Siphon tube 12 includes an intake portion 13 positioned in spaced relation with and in close proximity to the bottom of the container 1. Intake portion 13 is somewhat enlarged or flaring with respect to its tubular body and is disposed below the surface of the mercury bed 4. From its intake portion 13 the siphon member extends vertically upward into the neck portion of the container, then bends downwardly and extends outwardly passing through the lower side of the neck portion and terminates in a discharge end 14 at a substantial distance below container 1. A valve 18 provides a control of the siphon discharge which may be a volume control in continuous operation. Intermediate the intake and discharge portions of the siphon 12 there is provided three spaced chambers or enlarged portions 15 which are generally globular in shape. Globular portions 15 function as sorting chambers to separate a portion of elevated amalgam and free mercury which is entrained in the discharge flow created by the siphoning action. On reaching one of the chambers 15, the heavier mercury spreads from the flow and deposits along the inner walls of chambers 15 and then returns by gravity flow through siphon 12 to the mercury bed below. This sorting action results in additional contacting of metallic particles rising with the discharge flow by the gravitation flow of mercury or amalgam.

Metal-laden mercury or amalgam collecting in the mercury bed is drained through a valve 16 in the bottom of container 1 and discharges into an intermediate transport conduit 19 which extends from the discharge portion 14 of the siphon tube to the inlet of a final separator hereafter described. This amalgam withdrawal may be intermittent or continuous after an initial start-up period.

One or a plurality of amalgamators similar to container 1 with associated structure as described above may be connected in a series for further amalgamation of the discharge flow from siphon tube 12. One such similar amalgamator is shown in FIG. 1 by box 31 below container 1 with associated conduits illustrated in broken lines. An inlet conduit 33 having its intake portion connected to transport conduit 19 between the discharge portion 14 of the siphon tube 12 and the outlet portion of valve 16 passes the discharge flow from siphon tube 12 to the Water inlet 35 of amalgamator 31. An outlet conduit 37 conducts the discharge flow from the siphon tube of amalgamator 31 to conduit 19 downstream of the outlet of valve 16. The discharge fiow from amalgamator 31 is passed into conduit 19 downstream of the outlet of conduit 37 by conduit 16'. Additional amalgamators 31 with associated conduits receiving from and discharging into conduit 19 may be provided in a series sequence below container 1 to amalgamate the discharge flow as desired.

The hydrostatic head may be sufficient to provide the necessary velocity of the flow through inlet 35 to establish the desired centrifugal movement in the container of amalgamator 31 but it is understood that a pump similar to pump may be provided in conduit 33 to provide additional pressure if required.

A conduit portion 38 extends from transport conduit 19 which is arranged to direct the discharge flow against the inner surface of a centrifugal-type final separator 41. Thus, the discharge flow from the siphon tubes of container 1 and from amalgamator 31 and any multiple thereof when series operation is employed together with the amalgam discharge at valves 16 or 16' is passed through transport conduit 19 into conduit 38 and then in a centrifugal flow into separator 41 where the gangue is separated from the amalgam. It is understood that amalgam passing through valves 16 or 16 may each be conducted to separate separators distinct from that which handles the discharge flow from the siphon tubes but a single separator 41 at the end of the amalgamators as illustrated in FIG. 1 is preferred.

Separator 41 includes a centrally disposed overflow member 43 through which gangue is discharged. Amalgam settles in the bottom of the separator and is preferably intermittently drawn through a valve 45 disposed in the bottom thereof. The outlet of overflow member 43 is of sufficient capacity to discharge all of the flow provided through inlet conduit 38.

The operation of the above described amalgamation apparatus is as follows: The feed ore from conduit 6 discharges onto the mercury bed surface which is being swept by the centrifugal flow of water provided through inlet conduit 9 and outlet 9a or a plurality thereof. The centrifugal flow of water distributes the feed ore over the mercury surface agitating the mercury and effecting a primary separation of heavier metallic particles from the lighter gangue materials such as sand and crushed ore.

As the hydrostatic head in the container 1 increases pressure as the container fills with water, a portion of the mercury bed 4 is forced up into the siphon 12 when valve 18 is actuated to commence the siphoning action thereby exposing new mercury surfaces to contact with the ore flow. A sorting action in chambers develops a return flow of mercury and the siphon maintains a continuous Withdrawal of ore pulp. Also, when the siphoning action begins, water and ore are induced to circulate into and through the mercury bed in a discharge flow ascending up the siphon. The combined effect of the centrifugal action caused by the water introduced in tangential flow sweeping the ore over the surface of the mercury bed and the discharge flow created by the siphoning action agitates the mercury so that it is in constant motion. With the mercury agitation and ore flow therethrough new mercury surfaces then contact with the metal particles in the circulating ore to produce amalgam. As the water, ore, amalgam, and free mercury are pulled up the siphon member, the heavier amalgam and free mercury tend to push toward the outer periphery of the siphon and collect in the globular chambers 15. This elevated free mercury and amalgam then descend by gravitational flow through the siphon to the mercury bed below with mercury surfaces contacting particles of metal not previously amalgamated.

The apparatus above described will operate continuously if the water intake is greater than the siphon discharge and excess water may discharge through overflow tube 7. For-continuous operation, the hydrostatic head may be maintained substantially constant by balancing the water input and the discharge output.

The apparatus is self-adjusting and operates intermittently if the water intake is smaller than the siphon discharge. Under these conditions, the water level or hydrostatic head becomes lower and lower and finally the siphoning action is terminated by air intake. Valve 18 then is closed and the incoming water fills the container until there is a sufiicient hydrostatic head to start the siphoning action again. When the water supply is limited, the water may be separated from the gangue discharge and recirculated by a pump back to inlet conduit 9. Only a small quantity of replacement water is required for each cycle.

Variation in the control of the various input and discharge parameters to provide most efficient amalgamation will be apparent to those skilled in the art. Although I have illustrated a specific embodiment of my invention, various modifications will occur to those skilled in the art. Therefore, I do not desire my invention to be limited to the specific details illustrated and described, and I intend by the appended claims to cover all modifications which fall within the spirit and scope of my invention.

I claim:

1. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container, and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, and the enlarged portions retaining a portion of the free mercury and amalgam elevated with the ore discharge which is returned by gravitational flow to the mercury bed.

2. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said Container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container under a hydrostatic head, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, and the enlarged portions retaining a portion of the free mercury and amalgam elevated with the ore discharge which is returned by gravitational flow to the mercury bed.

3. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container, the intake portion being enlarged and disposed below the surface of said mercury bed and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, and the intermediate enlarged portions retaining a portion of the amalgam elevated with the ore discharge which is returned by gravitational flow to the mercury bed.

4. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge. of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediatet'the' surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container, and having a valve-controlled discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, and the enlarged portions retaining a portion of the amalgam elevated with the ore discharge which is returned by gravitational fiow to the mercury bed.

5. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced globular portions throughout its lengthwise extent intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, and the globular portions retaining a portion of the amalgam elevated with the ore discharger which is returned by gravitational flow to the mercury bed.

6. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from an in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, the enlarged portions retaining a portion of the amalgam elevated with the ore discharger which is returned by gravitational flow to the mercury bed, and means for removing the amalgam from said container.

7. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of.

the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, the enlarged portions retaining a portion of the amalgam elevated with the ore discharger which is returned by gravitational flow to the mercury bed, means for removing the amalgam from said container and means connected with the inflow of the feed ore for discharging excess water from the container.

8. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, the enlarged portions retaining a portion of the amalgam elevated with the ore discharger which is returned by gravitational flow to the mercury bed, and means for passing the discharge flow from said siphon to a similar second stage of amalgamation apparatus as feed water under pressure.

9. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, the enlarged portions retaining a portion of the amalgam elevated with the ore discharge which is returned by gravitational flow to the mercury bed, and means for passing the discharge flow from the siphon to an extractor inclusive of a container having a discharge outlet in its lower portion for amalgam and an overflow discharge outlet for gangue disposed at an elevated point in the container for a final separation of gangue from the amalgam.

10. Amalgamation apparatus comprising a closed cylindrical container, means for introducing mercury into said container to provide a bed of mercury in the bottom of said container, means for introducing a continuous charge of metallic ore in finely divided condition into the interior of said container, means for continuously directing water under pressure in tangential flow toward an inner upright wall portion of said container at a level intermediate the surface of said bed and the outlet of said ore feed means to thereby maintain centrifugal circulation of the contained ore, a tubular siphon member disposed centrally of the container with its intake portion spaced from and in close proximity to the bottom of the container and having a discharge portion extending out of an upper portion of the container, said siphon member having a plurality of vertically spaced enlarged portions intermediate the intake and discharge portions, the siphon member inducing circulation of ore into and through the mercury bed in a discharge flow, the combined effect of the centrifugal circulation and the discharge flow circulation agitating the mercury bed, thereby exposing new mercury surfaces into contact with the circulating ore to provide an amalgam, the enlarged portions retaining a portion of the amalgam elevated with the ore discharge which is returned by gravitational flow to the mercury bed, means for passing the discharge flow from said siphon to a similar stage of amalgamation apparatus as feed water under pressure, and means for passing the discharge flow from said similar stage to an extractor inclusive of a container having a discharge outlet in its lower portion for amalgam and an overflow discharge outlet for gangue disposed at an elevated point in the container for a final separation of gangue from the amalgam.

References Cited UNITED STATES PATENTS 529,047 11/1894 Pike 209189 872,555 12/1907 Capps 209-201 X 880,430 2/1908 Veitch 209189 3,282,422 11/1966 Reynolds 209-l58 FOREIGN PATENTS 350 1899 Great Britain.

FRANK W. LUTTER, Primary Examiner. 

1. AMALGAMATION APPARATUS COMPRISING A CLOSED CYLINDRICAL CONTAINER, A MEANS FOR INTRODUCING MERCURY INTO SAID CONTAINER TO PROVIDE A BED OF MERCURY IN THE BOTTOM OF SAID CONTAINER, MEANS FOR INTRODUCING A CONTINUOUS CHARGE OF METALLIC ORE IN FINELY DIVIDED CONDITION INTO THE INTERIOR OF SAID CONTAINER, MEANS FOR CONTINUOUSLY DIRECTING WATER UNDER PRESSURE IN TANGENTIAL FLOW TOWARD AN INNER UPRIGHT WALL PORTION OF SAID CONTAINER AT A LEVEL INTERMEDIATE THE SURFACE OF SAID BED AND THE OUTLET OF SAID ORE FEED MEANS TO THEREBY MAINTAIN CENTRIFUGAL CIRCULATION OF THE CONTAINED ORE, A TUBULAR SIPHON MEMBER DISPOSED CENTRALLY OF THE CONTAINER WITH ITS INTAKE PORTION SPACED FROM AND IN CLOSE PROXIMITY TO THE BOTTOM OF THE CONTAINER, AND HAVING A DISCHARGE PORTION EXTENDING OUT OF AN UPPER PORTION OF THE CONTAINER, SAID SIPHON MEMBER HAVING A PLURALITY OF VERTICALLY SPACED ENLARGED PORTIONS INTERMEDIATE THE INTAKE AND DISCHARGE PORTIONS, THE SIPHON MEMBER INCLUDING CIRCULATION OF ORE INTO AND THROUGH THE MERCURY BED IN A DISCHARGE FLOW, THE COMBINED EFFECT OF THE CENTRIFUGAL CIRCULATION AND THE DISCHARGE FLOW CIRCULATION AGITATING THE MERCURY BED, THEREBY EXPOSING NEW MERCURY SURFACES INTO CONTACT WITH THE CIRCULATING ORE TO PROVIDE AN AMALGAM, AND THE ENLARGED PORTIONS RETAINING A PORTION OF THE FREE MERCURY AND AMALGAM ELEVATED WITH THE ORE DISCHARGE WHICH IS RETURNED BY GRAVITATIONAL FLOW TO THE MERCURY BED. 